Preheat oven to 200°F (100°C). Line two baking sheets with Gefen Parchment Paper.

Place egg whites in mixer and add potato starch and salt. Beat on medium-high speed until frothy.

When the whites start to turn fluffy, add the sugars in a slow steady stream down the side of the bowl, making sure it all gets incorporated. Beat just until the whites are glossy, with firm peaks.

Spoon even-sized circles of meringue on each baking sheet, six to a sheet. Using the back of a spoon, swirl gently into a ring shape with high sides and a sunken middle, like slightly flat bowls. Alternatively, place meringue into a pastry bag and pipe from the center out so that your last circle is the rim of the bowl.

Place both sheets in the oven and bake meringues until dry, about two hours. Remove from oven and let cool completely for about one hour. They will crisp as they cool. Cool bowls completely before removing from parchment paper. Meringues can be made ahead and stored in an airtight container at room temperature.

Prepare the orange custard: Beat egg yolks until thick and fluffy in a bowl that will eventually act as the top of a double boiler.

Add in the sugar, zests, and citrus juices. Simmer in the double boiler until the mixture is thick and custard-like. Stir constantly. It should reach 155–160°F (68–71°C) when fully cooked, or very thick and custardy. Don’t overcook the custard, or it will start to separate.

Once the mixture is cooked and thickened, remove from the heat. Let the custard cool for about five minutes and then stir in the margarine.

Place in a bowl with plastic wrap directly on the custard’s surface to avoid a custard skin. Chill well but do not freeze.

Prepare whipped cream: Place parve whipping cream in an electric mixer and bring to a froth; add vanilla. Beat until peaks are formed.

Prepare chocolate base: Place one and a half bars of chocolate into the food processor and grind, using pulses, until it looks like coarse, ground chocolate.

Prepare chocolate curls: Use the remaining chocolate to create decorative curls for garnish. Hold the chocolate bar in your hands for a minute before beginning to peel. The heat from your hand will warm the chocolate slightly and make peeling curls easier. Using a vegetable peeler held over a plate or paper towel, peel long pieces of chocolate from the thin edge of the bar. The chocolate should turn into curls as it falls.

Plate each meringue bowl on a separate dessert plate.

Spoon two teaspoons ground chocolate into the center of each bowl, covering the bottom.

Spoon about one and a half tablespoons orange custard on top of the ground chocolate. Add a generous dollop of whipped cream to the center of the orange custard, leaving a ring of orange around the edges.

Using a spoon (your hands will melt the chocolate), sprinkle some of the curls in the center of the cream. Serve immediately.